Power supply circuit, power supply device and control method

ABSTRACT

Provided are a power supply circuit, a power supply device and a control method. The power supply circuit includes a primary rectifier unit, a modulation unit, a transformer, a secondary rectifier and filtering unit, and a control unit. In the power supply circuit, a liquid electrolytic capacitor at a primary side is removed, such that a volume of the power supply circuit is smaller, and is safe to use. Moreover, an output current of the power supply circuit has a periodically changing current value, and the control unit can control the duration of the output current in which the current value is 0.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2017/102932, filed Sep. 22, 2017, the entire disclosure of whichis incorporated herein by reference.

TECHNICAL FIELD

The present disclosure generally relates to a charging technology field,and more particularly, to a power supply circuit, a power supply deviceand a control method.

BACKGROUND

A power supply circuit typically includes a primary conversion unit anda secondary conversion unit. The primary conversion unit generallyincludes a primary rectifier unit and a primary filtering unit. Theprimary filtering unit typically adopts one or more high-capacity liquidelectrolytic capacitors (such as, liquid aluminum electrolyticcapacitors) to perform primary filtering on a voltage after primaryrectification.

The liquid electrolytic capacitor has disadvantages of short life andeasy cracking, resulting in a short life and insecurity of aconventional power supply circuit.

SUMMARY

The present disclosure provides a power supply circuit, a power supplydevice and a control method.

In a first aspect, a power supply circuit is provided. The power supplycircuit includes: a primary rectifier unit, configured to performrectification on input alternating current to output a first voltagehaving a periodically changing voltage value; a modulation unit,configured to modulate the first voltage to generate a second voltage; atransformer, configured to generate a third voltage based on the secondvoltage; a secondary rectifier and filtering unit, configured to performrectification and filtering on the third voltage to generate a fourthvoltage and a first current corresponding to the fourth voltage; and acontrol unit, configured to adjust the first current to generate anoutput current of the power supply circuit, the output current having asecond waveform with a current value periodically changing, and eachperiod of the second waveform containing a duration in which the currentvalue is 0.

In a second aspect, a power supply device is provided. The power supplydevice includes a housing, a circuit board, and a power supply circuit.The circuit board is enclosed by the housing. The power supply circuitis positioned on the circuit board, and the power supply circuit is asdescribed in the first aspect.

In a third aspect, a control method of a power supply circuit isprovided. The control method includes: performing rectification on inputalternating current to output a first voltage having a periodicallychanging voltage value; modulating the first voltage to generate asecond voltage; generating a third voltage based on the second voltage;performing rectification and filtering on the third voltage to generatea fourth voltage and a first current corresponding to the fourthvoltage; and adjusting the first current to generate an output currentof the power supply circuit, the output current having a second waveformwith a current value periodically changing, and each period of thesecond waveform containing a duration in which the current value is 0.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a power supply circuit according to anembodiment of the present disclosure.

FIG. 2 is a schematic diagram illustrating a waveform of a first voltageto be modulated according to an embodiment of the present disclosure.

FIG. 3 is a schematic diagram comparing voltage waveforms before andafter modulation of a conventional power supply circuit.

FIG. 4 is a schematic diagram illustrating a waveform of a secondvoltage obtained after modulating a first voltage according to anembodiment of the present disclosure.

FIG. 5 is a schematic diagram illustrating a first waveform aftersecondary rectification and filtering according to an embodiment of thepresent disclosure.

FIG. 6 is a schematic diagram of a power supply circuit according toanother embodiment of the present disclosure.

FIG. 7 is a schematic diagram illustrating a waveform of an outputcurrent and a waveform of a control signal for generating the waveformof the output current according to an embodiment of the presentdisclosure.

FIG. 8 is a schematic diagram of a power supply circuit according to yetanother embodiment of the present disclosure.

FIG. 9 is a schematic diagram of a power supply circuit according tostill another embodiment of the present disclosure.

FIG. 10 is a schematic diagram illustrating a fast charging processaccording to an embodiment of the present disclosure.

FIG. 11 is a block diagram of a power supply device according to anembodiment of the present disclosure.

FIG. 12 is a schematic flow chart of a control method according to anembodiment of the present disclosure.

DETAILED DESCRIPTION

In the related art, both a primary rectifier unit and a primaryfiltering unit are provided at a primary side of a power supply circuit.The primary filtering unit generally includes one or more liquidelectrolytic capacitors. The liquid electrolytic capacitor hasproperties of large capacity and strong filtering ability. Due to theexistence of the liquid electrolytic capacitor, an output provided bythe power supply circuit may be a constant direct current. However, theliquid electrolytic capacitor has disadvantages of short life and easycracking, resulting in a short life and insecurity of the power supplycircuit. Moreover, charging a battery in a device to be charged with theconstant direct current will result in polarization and lithiumprecipitation of the battery, such that a service life of the batterymay be reduced.

In order to improve the service life and safety of the power supplycircuit, and to relieve the polarization and lithium precipitation ofthe battery during charging process, embodiments of the presentdisclosure provide a power supply circuit without the liquidelectrolytic capacitor at the primary side. Such a power supply circuitmay be used to charge the battery in the device to be charged.

The device to be charged used in embodiments of the present disclosuremay refer to a mobile terminal, such as a “communication terminal” (or“terminal” for short). The “terminal” may include, but is not limited toa device configured to receive/transmit communication signals via awired connection (for example, public switched telephone network (PSTN),digital subscriber line (DSL) connection, digital cable connection,direct cable connection and/or another data connection/network) and/orvia a wireless interface (for example, cellular network, wireless localarea network (WLAN), digital TV network such as digital videobroadcasting handheld (DVB-H) network, satellite network, an amplitudemodulation-frequency modulation (AM-FM) broadcasting transmitter, and/ora wireless interface of another communication terminal). Thecommunication terminal configured to communicate via the wirelessinterface may be referred to as “wireless communication terminal”,“wireless terminal” and/or “mobile terminal”. Examples of a mobileterminal include, but are not limited to a satellite phone or a cellphone, a terminal combining a cell radio phone and a personalcommunication system (PCS) having capability of data process, fax, anddata communication, a personal digital assistant (PDA) including a radiophone, a pager, Internet/Intranet access, a web browser, a note pad &address book, a calendar and/or a global positioning system (GPS)receiver, and a common laptop and/or handheld receiver, or otherelectronic devices including a radio phone transceiver.

As illustrated in FIG. 1, the power supply circuit 10 according to anembodiment of the present disclosure may include a primary rectifierunit 11, a modulation unit 12, a transformer 13, and a secondaryrectifier and filtering unit 14. In the following, respective componentsof the power supply circuit 10 will be described in detail respectively.

The primary rectifier unit 11 may be configured to perform rectificationon input alternating current to output a first voltage having aperiodically changing voltage value. In some cases, the inputalternating current (AC) may be referred to as mains supply. The inputalternating current may be 220V alternating current, or may be 110Valternating current, which is not limited in embodiments of the presentdisclosure.

A voltage waveform of the first voltage is periodically changing. Asillustrated in FIG. 2, the waveform of the first voltage may be apulsating waveform or a steamed bun waveform.

Implementation of the primary rectifier unit 11 is not limited inembodiments of the present disclosure. The primary rectifier unit 11 maybe a full-bridge rectifier circuit formed of four diodes, or may be arectifier circuit in other forms, such as a half-bridge rectifiercircuit.

The modulation unit 12 may be configured to modulate the first voltageto generate a second voltage. In some cases, the modulation unit 12 maybe referred to as a chopper unit or a chopper. In other cases, themodulation unit 12 may be referred to as a clipper unit or a clipper. Inembodiments of the present disclosure, implementation of the modulationunit 12 is not limited. As an example, the modulation unit 12 may modulethe first voltage in a PWM (Pulse Width Modulation) mode, or maymodulate the first voltage in a frequency modulation mode.

It should be noted that, in the related art, a voltage output from theprimary rectifier unit 11 (corresponding to the first voltage inembodiments of the present disclosure) needs to be filtered by theprimary filtering unit (including one or more liquid electrolyticcapacitors) to form the constant direct current. A voltage waveform ofthe constant direct current is typically a straight line, i.e., thevoltage waveform before modulation as illustrated in FIG. 3. Then, themodulation unit modulates the constant voltage (chops the waveform), toform the voltage after modulation as illustrated in FIG. 3. It can beseen from FIG. 3 that, with the processing of the modulation unit, theconstant voltage signal is chopped into many small square wave pulsesignals with same amplitude.

In contrast, the power supply circuit provided by embodiments of thepresent disclosure removes the liquid electrolytic capacitor for primaryfiltering, and directly modulates the first voltage having theperiodically changing voltage value after the primary rectification.Taking the waveform of the first voltage illustrated in FIG. 2 as anexample, the waveform of the second voltage obtained after themodulation may be as illustrated in FIG. 4. It can be seen from FIG. 4that, the second voltage also contains may small pulse signals, however,amplitudes of these pulse signals are not identical and changeperiodically. The dashed line in FIG. 4 indicates an envelope of pulsesignals forming the second voltage. Compared with FIG. 2, the envelopeof pulse signals forming the second voltage is substantially same as thewaveform of the first voltage.

The transformer 13 may be configured to generate a third voltage basedon the second voltage. In other words, the transformer 13 may beconfigured to couple the second voltage from the primary side of thetransformer 13 to the secondary side of the transformer 13, to obtainthe third voltage. For example, the transformer 13 may be configured toperform voltage transformation related operation on the second voltageto obtain the third voltage. The transformer 13 may be a commontransformer, or may be a high-frequency transformer of which a workingfrequency ranges from 50 KHz to 2 MHz. The transformer 13 may include aprimary winding and a secondary winding. Forms of the primary windingand the secondary winding, and connection modes between the primarywinding and secondary winding and other units in the power supplycircuit 10 are related to types of a switching power supply used by thepower supply circuit. For example, the power supply circuit 10 may bebased on a flyback switching power supply, a forward switching powersupply, or a push-pull switching power supply. With different types ofthe switching power supply on which the power supply circuit is based,the specific forms and the connection modes of the primary winding andthe secondary winding of the transformer may be different, which is notlimited in embodiments of the present disclosure. FIG. 1 merelyillustrates one possible connection mode of the transformer 13.

The secondary rectifier and filtering unit 14 may include a secondaryrectifier unit and a secondary filtering unit. The filtering mode of thesecondary filtering unit is not limited in embodiments of the presentdisclosure. As an example, the secondary filtering unit may adopt a SR(synchronous rectifier) chip to perform synchronous rectification on thevoltage (or current) induced by the secondary winding of thetransformer. As another example, the secondary filtering unit may adopta diode to perform secondary rectification. The secondary filtering unitmay be configured to perform secondary filtering on the voltage afterthe secondary rectification. The secondary filtering unit may includeone or more solid capacitors, or may include a combination of solidcapacitors and common capacitors (such as, ceramic capacitors).

After the processing of the secondary rectifier and filtering unit 14, afourth voltage and a first current corresponding to the fourth voltagemay be obtained. In the following, a waveform of the first current isreferred to as a first waveform. The solid line in FIG. 5 illustratesone example of the first waveform. It can be seen from FIG. 5 that, thefirst waveform does not have a constant current value, but have aperiodically changing current value, the reason which is explained asfollows.

Since the liquid electrolytic capacitor is removed from the primary sideof the power supply circuit 10, the second voltage input into thetransformer 13 consists of many small pulse signals whose amplitudesperiodically changes. Likewise, the third voltage transmitted to thesecondary side by the transformer 13 also consists of many small pulsesignals whose amplitudes periodically change. The secondary filteringcapacitor is provided in the secondary rectifier and filtering unit 14.However, compared with the liquid electrolytic capacitor, the secondaryfiltering capacitor typically adopts some low-capacity solid capacitors.A capacitance of the solid capacitor is generally low, and a filteringability of the solid capacitor is relatively lower. Therefore, thesecondary filtering capacitor is mainly configured to filter many smallpulse signals outputted after the secondary rectification into acontinuous signal which periodically changes. The waveform of thiscontinuous signal is similar to the envelope of these small pulsesignals.

Further, it can be seen from FIG. 5 that, the first waveform is not acomplete pulsating waveform. Neither Peaks nor valleys of the firstwaveform reach peaks and valleys of the pulsating waveform (dashed linein FIG. 5). The reasons why peaks of the first waveform do not reach thepeaks of the pulsating waveform are mainly in that the power supplycircuit 10 generally monitors the output voltage and/or the outputcurrent of itself, and performs voltage limiting operation on the outputvoltage and/or performs current limiting operation on the outputcurrent. the voltage limiting and/or current limiting operation willlimit the peaks of the pulsating waveform under a preset magnitude, suchthat the first waveform after peak clipping as illustrated in FIG. 5 isformed.

The reasons why valleys of the first waveform do not reach the valleysof the pulsating waveform are mainly in that the secondary filteringcapacitor in the secondary rectifier and filtering unit has a clampingrole for a voltage on a charging line at the secondary side, such thatthe voltage and current on the charging line at the secondary sidecannot reach zero point. In detail, when the voltage on the chargingline at the secondary side drops to be equal to the voltage value of thesecondary filtering capacitor, the secondary filtering capacitor entersa discharging state, such that the voltage on the charging line does notcontinue to drop, thus clamping the valley of the first waveform at acertain value greater than zero. The specific size of this value isrelated to the capacitance of the secondary filtering capacitor, whichis not limited in embodiments of the present disclosure.

It can be seen from the above description that, in the power supplycircuit 10 provided by embodiments of the present disclosure, the liquidelectrolytic capacitor at the primary side is removed, such that thevolume of the power supply circuit is reduced, and the service life andsafety of the power supply circuit is improved.

The power supply circuit 10 may be used to charge the battery in thedevice to be charged. During the charging process, if the battery may becontrolled to charge and discharge periodically, polarization andlithium precipitation of the battery may be reduced significantly, thusimproving the service life and safety of the battery. However, based onthe above description related to the secondary filtering, the secondaryfiltering capacitor in the secondary rectifier and filtering unit 14 hasthe clamping role for the voltage on the charging line of the powersupply circuit 10, resulting in that the valleys of the waveform of thefirst current obtained after the secondary filtering (i.e., the firstwaveform) cannot reach zero points. if the first current is directlyoutputted as the output current of the power supply circuit 10, sincethe first current cannot reach zero points, the battery in the device tobe charged may be always in the charging state, which cannot ensure theperiodical discharging of the battery.

Further, in embodiments of the present disclosure, in order to ensurethat the battery can charge and discharge periodically, the power supplycircuit 10 may further include a control unit 15. The control unit 15may be configured to adjust the first current to generate the outputcurrent of the power supply circuit 10. The output current of the powersupply circuit 10 may have a second waveform with a periodicallychanging current value, and each period of the second waveform includesa duration in which the current value is zero.

Each period of the second waveform includes a duration in which thecurrent value is zero and a duration in which the current value is notzero. For the sake of description, the duration in which the currentvalue is zero is referred to as a first duration, and the duration inwhich the current value is not zero is referred to as a second duration.The second waveform is a waveform of the output current. The currentvalue of the output current in the first duration being zero means thatthere is no output from the power supply circuit 10 in the firstduration. At this time, since the battery in the device to be chargingtypically needs to charge the system of the device to be chargedcontinuously, the battery is in the discharging state. The current valueof the output current in the second duration being not zero means thatthe output of the power supply circuit 10 is recovered in the secondduration. At this time, the battery in the device to be charged is inthe charging state. It can be seen that, since each period of the secondwaveform has the first duration in which the current value is zero andthe second duration in which the current value is not zero, the batteryin the device to be charged may enter a periodical charging anddischarging state, thus significantly reducing the polarization andlithium precipitation of the battery, and improving the service life andsafety of the battery.

The control unit 15 may be an MCU (micro-control unit). The control unit15 may control other units in the power supply circuit 10 by sending acontrol signal to other units in the power supply circuit 10. Thecontrol unit 15 may adjust the first current in various ways, andaccordingly, the control unit 15 may be coupled to the other units ofthe power supply circuit 10 in various ways, which is not limited inembodiments of the present disclosure. Illustration may be made belowwith reference to FIGS. 6-9.

FIG. 6 illustrate an embodiment in which the control unit 15 adjusts thefirst current to form the output current crossing zero points. Asillustrated in FIG. 6, the power supply circuit 10 may further include afirst switch unit 60 configured to control the charging line 61 of thepower supply circuit 10 to switch on or off. The charging line 61 may beconfigured to transmit electric energy. In other words, the chargingline 61 may be configured to transmit a charging voltage and/or acharging current to the device to be charged. Taking the power supplycircuit 10 charging the device to be charged via a USB (universal serialbus) as an example, the charging line 61 may be for example a VBUS ofthe USB.

The first switch unit 62 may be any element having a line on-off controlfunction. As illustrated in FIG. 6, the first switch unit 62 may be aMOS (metal oxide semiconductor) transistor. A gate of the MOS transistormay be coupled to the control unit 15, for receiving the control signalsent by the control unit 15. A source and a drain of the MOS transistormay be coupled in serial in the charging line 61, such that the chargingline 61 may be controlled to switch on or off under the control of thecontrol signal.

Further, the control unit 15 may be configured to control the firstswitch unit 62 to switch off in a part of each period of the firstwaveform, to switch off the output of the power supply circuit 10.

The ways for selecting the above part of each period is not limited inembodiments of the present disclosure, and any one or more durations ofeach period of the first waveform may be selected as the above part ofeach period.

As an example, the above part of each period may be the duration wherethe valley of the first waveform is located. In other words, the controlunit 15 may control the first switch unit 62 to switch off in a part ofall of the duration in which the first waveform is at the valley, toswitch off the output of the power supply circuit 10. Compared withcontrolling the first switch unit 62 to switch off in the duration ofeach period other than the duration where the valley is located,controlling the first switch unit 62 to switch off in the duration ofeach period where the valley is located may ensure a charging efficiencyof the battery to the maximum extent while satisfying the periodicalcharging and discharging of the battery.

Assume that the control unit 15 controls the first switch unit 62 toswitch off in a part or all of the duration in which the first waveformis at the valley, the control unit 15 determines the duration where thevalley of the first waveform is located in various ways. As an example,the control unit 15 samples the first current, and determines theduration where the valley of the first waveform is located according tothe sampling value of the first current. As another example, the periodof the first waveform has a synchronization relationship with many othersignals in the power supply circuit 10, for example, the voltage signalor current signal outputted by the primary rectifier unit, the voltagesignal or current signal outputted by the secondary rectifier unit, andthe like. These signals are referred to as synchronization signals ofthe first current in the following. The control unit 15 may determinethe duration where the valley of the first waveform is located accordingto the waveform of the synchronization signal, and the synchronizationrelationship between the waveform of the synchronization signal and thefirst waveform.

Taking the first waveform being the waveform represented by the solidline in FIG. 5 as an example, the control unit 15 may send the controlsignal as illustrated in FIG. 7 to the first switch unit 62, to controlthe power supply circuit 10 to stop outputting in the duration where thevalley of the first waveform is located, such that the second waveformincluding the duration in which the current value is zero as illustratedin FIG. 7 may be formed.

FIG. 8 illustrates another embodiment in which the control unit 15adjusts the first current to form the output current crossing zeropoints. As illustrated in FIG. 8, the power supply circuit 10 mayfurther include a load circuit 81 coupled in parallel with a chargingloop of the power supply circuit 10, and a second switch unit 82configured to control the load circuit 81 to switch on or off.

The charging loop may be formed by the charging line and a ground line.Taking the power supply circuit charging the device to be charged viathe BUS as an example, the charging loop may be formed by the VBUS andGND.

In embodiments of the present disclosure, in order to achieve a purposethat the output current of the power supply circuit may reach 0, theload circuit 81 is introduced in the power supply circuit 10. With theconfiguration of load on the load circuit 81, all the electric energytransmitted on the charging loop may be consumed by the load in the loadcircuit 81 when the second switch unit 82 is switched on.

In embodiments of the present disclosure, implementation of the load onthe load circuit 81 is not limited. The load may be for example aresistor, or may be other elements that can be used to consume electricenergy. Moreover, a size of the load may be determined according toactual situation, as long as all the electric energy on the chargingloop may be consumed by the load circuit 81 when the second switch unit82 is switched on.

The control unit 15 may be configured to control the second switch unit82 to switch on in a part of each period of the first waveform. When thesecond switch unit is switched on, the load circuit 81 is in a workingstate, and the electric energy on the charging loop may be consumed bythe load circuit 81 and may not be outputted to the outside of the powersupply circuit 10. Therefore, when the load circuit 81 is in the workingstate, the output current of the power supply circuit 10 is zero.

The above part of each period mentioned in embodiments of the presentdisclosure (i.e., the duration in which the load circuit 81 is in theworking state) may be selected in ways same as those in the embodimentof FIG. 6, and reference may be made to the foregoing descriptionrelated to the embodiment of FIG. 6, which will not be elaborated foravoiding repetition.

FIG. 9 illustrates yet another embodiment in which the control unit 15adjusts the first current to form the output current crossing zeropoints. As illustrated in FIG. 9, the secondary rectifier and filteringunit 14 may include a filtering circuit 141 (it is to be understoodthat, the secondary rectifier and filtering unit 14 may include elementsrelated to secondary rectification, but for sake of clarity, FIG. 9 onlyillustrates elements related to this embodiment in the secondaryrectifier and filtering unit 14). The filtering circuit 141 may consistsof one or more capacitors (such as solid capacitors) coupled inparallel. The filtering circuit 141 may further include a third switchunit 142 configured to control the filtering circuit 141 to switch on oroff. When the third switch unit 142 is switched on, the filteringcircuit 141 is in the working state, having a clamping role for thevoltage on the charging line of the power supply circuit 10, resultingin that the output current of the power supply circuit 10 cannot reachzero. In this embodiment, in order to enable to the output current ofthe power supply circuit 10 to reach zero, the control unit 15 controlsthe third switch unit 142 to switch off in a target duration of eachperiod of the first waveform, in which the target duration is theduration where the valley of the first waveform is located. Since thetarget duration is the duration where the valley of the first waveformis located, the capacitor in the filtering circuit 141 should be in thedischarging state in the target duration. However, in the targetduration, since the control unit 15 controls the filtering circuit 141via the third switch unit 142 to stop working, the capacitor in thefiltering circuit 141 cannot discharge, and thus there is no output formthe power supply circuit 10. In this way, the output current of thepower supply circuit is zero in the target duration.

Further, in the embodiment corresponding to FIG. 9, the third switchunit 142 may include a MOS transistor. A positive electrode of thefiltering capacitor 143 may be coupled to the charging line (such asVBUS) of the power supply circuit 10, a negative electrode of thefiltering capacitor 143 may be coupled to a source of the MOStransistor, a drain of the MOS transistor may be coupled to ground (suchas GND), and a gate of the MOS transistor may be coupled to the controlunit 15. The source of the MOS transistor being coupled to the negativeelectrode of the filtering capacitor 143 may enable a cathode of a bulkdiode in the MOS transistor to ground, such that the filtering capacitor143 may not discharge to the bulk diode when the MOS transistor isswitched on.

In the related art, a power supply circuit for charging the device to becharged is proposed. This power supply circuit operates in a constantvoltage mode. In the constant voltage mode, the output voltage of thispower supply circuit keeps substantially constant, for example, 5V, 9V,12V or 20V.

The output voltage of the power supply circuit is not suitable for beingdirectly applied to both ends of the battery. Instead, the outputvoltage of the power supply circuit needs to be converted by aconversion circuit in the device to be charged, such that a chargingvoltage and/or a charging current expected by the battery in the deviceto be charged is obtained.

The conversion circuit is configured to convert the output voltage ofthe power supply circuit, to meet a requirement of the charging voltageand/or charging current expected by the battery.

As an example, the conversion circuit may be a charging managementmodule, such as a charging integrated circuit (IC). During a chargingprocess of the battery, the conversion circuit may be configured tomanage the charging voltage and/or charging current of the battery. Theconversion circuit may have at least one of a voltage feedback functionand a current feedback function, so as to manage the charging voltageand/or charging current of the battery.

For example, the charging process of the battery may include at leastone of a trickle charging stage, a constant current charging stage and aconstant voltage charging stage. In the trickle charging stage, theconversion circuit may utilize a current feedback loop to ensure that acurrent flowing into the battery in the trickle charging stage meets thecharging current (such as a first charging current) expected by thebattery. In the constant current charging stage, the conversion circuitmay utilize a current feedback loop to ensure that the current flowinginto the battery in the constant current charging stage meets thecharging current (such as a second charging current, which may begreater than the first charging current) expected by the battery. In theconstant voltage charging stage, the conversion circuit may utilize avoltage feedback loop to ensure that a voltage applied to both ends ofthe battery in the constant voltage charging stage meets the chargingvoltage expected by the battery.

As an example, when the output voltage of the power supply circuit isgreater than the charging voltage expected by the battery, theconversion circuit may be configured to perform a buck conversion on theoutput voltage of the power supply circuit to enable a buck-convertedcharging voltage to meet the requirement of the charging voltageexpected by the battery. As another example, when the output voltage ofthe power supply circuit is less than the charging voltage expected bythe battery, the conversion circuit may be configured to perform a boostconversion on the output voltage of the power supply circuit to enable aboost-converted charging voltage to meet the requirement of the chargingvoltage expected by the battery.

As another example, assume that the power supply circuit outputs aconstant voltage of 5V. When the battery includes a single battery cell(such as a lithium battery cell, a charging cut-off voltage of a singlebattery cell is typically 4.2V), the conversion circuit (for example, abuck circuit) may perform a buck conversion on the output voltage of thepower supply circuit, such that the charging voltage obtained after thebuck conversion meets a requirement of the charging voltage expected bythe battery.

As yet another example, assume that the power supply circuit outputs aconstant voltage of 5V. When the power supply circuit charges aplurality of (two or more) battery cells (such as lithium battery cell,a charging cut-off voltage of a single battery cell is typically 4.2V)coupled in series, the conversion circuit (for example, a boost circuit)may perform a boost conversion on the output voltage of the power supplycircuit, such that the charging voltage obtained after the boostconversion meets a requirement of the charging voltage expected by thebattery.

Limited by a poor conversion efficiency of the conversion circuit, apart of electric energy is lost in a form of heat, and the heat maygather inside the device to be charged. A design space and a space forheat dissipation of the device to be charged are small (for example, thephysical size of a mobile terminal used by a user becomes thinner andthinner, while plenty of electronic elements are densely arranged in themobile terminal to improve performance of the mobile terminal), whichnot only increases difficulty in designing the conversion circuit, butalso results in that it is hard to dissipate the heat gathered in thedevice to be charged, thus further causing an abnormity of the device tobe charged.

For example, the heat gathered on the conversion circuit may cause athermal interference on electronic elements neighboring the conversioncircuit, thus causing abnormal operations of the electronic elements;and/or for another example, the heat gathered on the conversion circuitmay shorten the service life of the conversion circuit and neighboringelectronic elements; and/or for yet another example, the heat gatheredon the conversion circuit may cause a thermal interference on thebattery, thus causing abnormal charging and/or abnormal discharging ofthe battery; and/or for still another example, the heat gathered on theconversion circuit may increase the temperature of the device to becharged, thus affecting user experience during the charging; and/or forstill yet another example, the heat gathered on the conversion circuitmay short-circuit the conversion circuit, such that the output voltageof the power supply circuit is directly applied to both ends of thebattery, thus causing abnormal charging of the battery, which bringssafety hazard if the over-voltage charging lasts for a long time, forexample, the battery may explode.

Embodiments of the present disclosure further provide a power supplycircuit 10. The control unit 15 in the power supply circuit 10 may beconfigured to communicate with the device to be charged, to adjust anoutput power of the power supply circuit 10, such that the outputvoltage and/or the output current of the power supply circuit 10 matchesa charging stage where the battery in the device to be charged iscurrently.

It should be understood that, the charging stage where the battery iscurrently may include at least one of a trickle charging stage, aconstant current charging stage and a constant voltage charging stage.

Taking the charging stage where the battery is currently being theconstant voltage charging stage as an example, communicating with thedevice to be charged, to adjust the output power of the power supplycircuit, such that the output voltage and/or the output current of thepower supply circuit matches the charging stage where the battery in thedevice to be charged is currently, includes: in the constant voltagecharging stage, communicating with the device to be charged, to adjustthe output power of the power supply circuit, such that the outputvoltage of the power supply circuit matches the charging voltagecorresponding to the constant voltage charging stage.

Taking the charging stage where the battery is currently being theconstant current charging stage as an example, communicating with thedevice to be charged, to adjust the output power of the power supplycircuit, such that the output voltage and/or the output current of thepower supply circuit matches the charging stage where the battery in thedevice to be charged is currently, includes: in the constant currentcharging stage, communicating with the device to be charged, to adjustthe output power of the power supply circuit, such that the outputcurrent of the power supply circuit matches the charging currentcorresponding to the constant current charging stage.

The power supply circuit 10 having communication function provided byembodiments of the present disclosure will be illustrated in detailbelow.

The power supply circuit 10 may obtain status information of thebattery. The status information of the battery may include presentelectric quantity information and/or voltage information of the battery.The power supply circuit 10 may adjust the output voltage of the powersupply circuit 10 itself according to he obtained status information ofthe battery, to meet the requirement of the charging voltage and/orcharging current expected by the battery. The voltage outputted by thepower supply circuit 10 after adjustment may be directly applied to bothends of the battery for charging the battery (hereinafter, referred toas “direct charging”). Further, during the constant current chargingstage of the process of charging the battery, the voltage outputted bythe power supply circuit 10 after adjustment may be directly applied toboth ends of the battery for charging the battery.

The power supply circuit 10 may have a voltage feedback function and acurrent feedback function, so as to manage the charging voltage and/orcharging current of the battery.

The power supply circuit 10 adjusting the output voltage of the powersupply circuit 10 itself according to the obtained status information ofthe battery may mean that, the power supply circuit 10 may obtain thestatus information of the battery in real time, and adjust the outputvoltage of the power supply circuit 10 itself according to the obtainedreal-time status information of the battery, to meet the chargingvoltage and/or charging current expected by the battery.

The power supply circuit 10 adjusting the output voltage of the powersupply circuit 10 itself according to the obtained real-time statusinformation of the battery may mean that, as the voltage of the batterycontinuously increases during the charging process, the power supplycircuit 10 may obtain the present status information of the battery atdifferent time points in the charging process, and adjust the outputvoltage of the power supply circuit 10 itself in real time according tothe present status information of the battery, to meet the requirementof the charging voltage and/or charging current expected by the battery.

For example, the charging process of the battery may include at leastone of a trickle charging stage, a constant current charging stage and aconstant voltage charging stage. In the trickle charging stage, thepower supply circuit 10 may output a first charging current in thetrickle charging stage to charge the battery, so as to meet therequirement of the charging current expected by the battery (the firstcharging current may be the constant direct current). In the constantcurrent charging stage, the power supply circuit 10 may utilize acurrent feedback loop to ensure that the current outputted by the powersupply circuit 10 and flowing into the battery in the constant currentcharging stage meets the requirement of the charging current expected bythe battery (such as a second charging current, which may also be acurrent with a pulsating waveform, and may be greater than the firstcharging current, which may mean that, a peak value of the current withthe pulsating waveform in the constant current charging stage is greaterthan that of the current with the pulsating waveform in the tricklecharging stage, while “constant current” of the constant currentcharging stage means that, in the constant current charging stage, apeak value or a mean value of the current with the pulsating waveform isbasically constant). In the constant voltage charging stage, the powersupply circuit 10 may utilize a voltage feedback loop to ensure that avoltage outputted from the power supply circuit 10 to the device to becharged in the constant voltage charging stage (i.e., the constantdirect voltage) keeps constant.

For example, the power supply circuit 10 mentioned in embodiments of thepresent disclosure may be mainly configured to control the constantcurrent charging stage of the battery in the device to be charged. Inother embodiments, controlling the trickle charging stage and theconstant voltage charging stage of the battery in the device to becharged may also be completed cooperatively by the power supply circuit10 and an additional charging chip in the device to be charged. Comparedto that in the constant current charging stage, the charging poweraccepted by the battery in the trickle charging stage and the constantvoltage charging stage is less, and the efficiency conversion loss andthe heat accumulation of the charging chip in the device to be chargedis acceptable.

It should be noted that, the constant current charging stage or theconstant current stage mentioned in embodiments of the presentdisclosure may refer to a charging mode in which the output current ofthe power supply circuit 10 is controlled, and does not require theoutput current of the power supply circuit 10 to keep completelyconstant and unchanged. For example, the constant current may refer tothat, a peak value or a mean value of the current with the pulsatingwaveform outputted by the power adapter is basically constant, or keepsconstant during a certain time period. For example, in practice, thepower supply circuit 10 typically performs charging by means ofmulti-stage constant current charging in the constant current chargingstage.

The multi-stage constant current charging may include N constant currentstages, where N is an integer no less than 2. The first charging stageof the multi-stage constant current charging starts with a predeterminedcharging current. N constant current stages in the multi-stage constantcurrent charging are performed in sequence from the first charging stageto the (N-1)^(th) charging stage. After the constant current charging isswitched from one constant current stage to the next constant currentstage, the peak value of the current may be decreased. When the batteryvoltage reaches a charging stop voltage threshold, the constant currentcharging is switched from the present constant current stage to the nextconstant current stage. The current change between two adjacent constantcurrent stages may be gradual, or may be in a stepped skip manner.

Further, in a case where the output current of the power supply circuit10 is the current having the current value periodically changing (suchas the pulsating direct current), the constant current mode may refer toa charging mode in which the peak value or the mean value of the currentperiodically changing is controlled, i.e., the peak value of the outputcurrent of the power supply circuit 10 is controlled to not exceed thecurrent corresponding to the constant current mode. Moreover, in a casewhere the output current of the power supply circuit 10 is thealternating current, the constant current mode refers to a charging modein which the peak value of the alternating current is controlled.

In some embodiments, the power supply circuit 10 supports a firstcharging mode and a second charging mode, and a charging speed of thepower supply circuit 10 charging the battery in the second charging modeis greater than a charging mode of the power supply circuit 10 chargingthe battery in the first charging mode. In other words, compared to thepower supply circuit 10 working in the first charging mode, the powersupply circuit 10 working in the second charging mode may take a shortertime to fully charge the battery with a same capacity. Further, in someembodiments, in the first charging mode, the power supply circuit 10charges the battery via a second charging channel, and in the secondcharging mode, the power supply circuit 10 charges the battery via afirst charging channel.

The first charging mode may be a normal charging mode, and the secondcharging mode may be a fast charging mode. The normal charging mode mayrefer to a charging mode in which the power supply circuit 10 outputs arelatively smaller current value (typically less than 2.5 A) or chargesthe battery in the device to be charged with a relatively smaller power(typically less than 15). In the normal charging mode, it typicallytakes several hours to fully fill a larger capacity battery (such as abattery with 3000 mAh). However, in the fast charging mode, the powersupply circuit 10 can output a relatively large current (typicallygreater than 2.5 A, such as 4.5 A, 5 A or higher) or charges the batteryin the device to be charged with a relatively large power (typicallygreater than or equal to 15 W). Compared to the normal charging mode,the period of time may be significantly shortened when the battery withthe same capacity is fully filled by the power supply circuit 10 in thefast charging mode, and the charging is faster.

As indicated above, the output current of the power supply circuit 10may have the second waveform with the current value periodicallychanging. The second waveform may refer to the current waveform of theoutput current of the power supply circuit 10 working in the secondcharging mode. In the first charging mode, the voltage value of theoutput voltage of the power supply circuit 10 is constant, and thecurrent waveform of the output current varies with the load.

Further, the device to be charged may perform bidirectionalcommunication with the power supply circuit 10 (or the control unit 15in the power supply circuit 10), to control the output of the powersupply circuit 10 in the second charging mode (i.e., control thecharging voltage and/or the charging current provided by the powersupply circuit 10 in the second charging mode). The device to be chargedmay include a charging interface, and the device to be charged maycommunicate with the power supply circuit 10 via a data wire of thecharging interface. Taking the charging interface being a USB interfaceas an example, the data wire may be a D+ wire and/or a D− wire of theUSB interface. Or, the device to be charged may perform wirelesscommunication with the power supply circuit 10.

The communicated content between the power supply circuit 10 and thedevice to be charged is not limited in embodiments of the presentdisclosure, and the control method of the device to be charged on theoutput of the power supply circuit 10 in the second charging mode isalso not limited in embodiments of the present disclosure. For example,the device to be charged may communicate with the power supply circuit10 to obtain the present voltage or present electric quantity of thebattery in the device to be charged, and adjust the output voltage oroutput current of the power supply circuit 10 based on the presentvoltage or present electric quantity of the battery. In the following,the communicated content between the power supply circuit 10 and thedevice to be charged and the control method of the device to be chargedon the output of the power supply circuit 10 in the second charging modewill be described in detail in combination with specific embodiments.

The master-slave relation of the power supply circuit 10 and the deviceto be charged is not limited in embodiments of the present disclosure.In other words, any of the power supply circuit 10 and the device to becharged can be configured as the master device for initiating thebidirectional communication session, accordingly, the other one can beconfigured as the slave device for making a first response or a firstreply to the communication initiated by the master device. As a feasibleimplementation, during the communication, the identities of the masterdevice and the slave device can be determined by comparing theelectrical levels of the power supply circuit 10 and the device to becharged relative to the ground.

The specific implementation of bidirectional communication between thepower supply circuit 10 and the device to be charged is not limited inembodiments of the present disclosure. In other words, any of the powersupply circuit 10 and the device to be charged can be configured as themaster device for initiating the communication session, accordingly, theother one can be configured as the slave device making a first responseor a first reply to the communication session initiated by the masterdevice, and the master device is able to make a second response to thefirst response or the first reply of the slave device, and thus anegotiation about a charging mode can be realized between the masterdevice and the slave device. As a feasible implementation, a chargingoperation between the master device and the slave device is performedafter a plurality of negotiations about the charging mode are completedbetween the master device and the slave device, such that the chargingprocess can be performed safely and reliably after the negotiation.

As an implementation, the mater device is able to make a second responseto the first response or the first reply made by the slave device to thecommunication session in a manner that, the master device is able toreceive the first response or the first reply made by the slave deviceto the communication session and to make a targeted second response tothe first response or the first reply. As an example, when the masterdevice receives the first response or the first reply made by the slavedevice to the communication session in a predetermined time period, themaster device makes the targeted second response to the first responseor the first reply of the slave device in a manner that, the masterdevice and the slave device complete one negotiation about the chargingmode, and a charging process may be performed between the master deviceand the salve device in the first charging mode or the second chargingmode, i.e., the power supply circuit 10 charges the device to be chargedin the first charging mode or the second charging mode according to anegotiation result.

As another implementation, the mater device is able to make a secondresponse to the first response or the first reply made by the slavedevice to the communication session in a manner that, when the masterdevice does not receive the first response or the first reply made bythe slave device to the communication session in the predetermined timeperiod, the mater device also makes the targeted second response to thefirst response or the first reply of the slave device. As an example,when the master device does not receive the first response or the firstreply made by the slave device to the communication session in thepredetermined time period, the mater device makes the targeted secondresponse to the first response or the first reply of the slave device ina manner that, the master device and the slave device complete onenegotiation about the charging mode, and the charging process isperformed between the mater device and the slave device in the firstcharging mode, i.e., the power supply circuit 10 charges the device tobe charged in the first charging mode.

In some embodiments, when the device to be charged is configured as themater device for initiating the communication session, after the powersupply circuit 10 configured as the slave device makes the firstresponse or the first reply to the communication session initiated bythe master device, it is unnecessary for the device to be charged tomake the targeted second response to the first response or the firstreply of the power supply circuit 10, i.e., one negotiation about thecharging mode is regarded as completed between the power supply circuit10 and the device to be charged, and the power supply circuit 10 is ableto charge the device to be charged in the first charging mode or thesecond charging mode according to the negotiation result.

In some embodiments, the device to be charged may perform bidirectionalcommunication with the power supply circuit 10 to control the output ofthe power supply circuit 10 in the second charging mode as follows. Thedevice to be charged performs the bidirectional communication with thepower supply circuit 10 to negotiate the charging mode between the powersupply circuit 10 and the device to be charged.

In some embodiments, the device to be charged may perform thebidirectional communication with the power supply circuit 10 tonegotiate the charging mode between the power supply circuit 10 and thedevice to be charged as follows. The device to be charged receives afirst instruction sent by the power supply circuit 10, in which thefirst instruction is configured to query the device to be chargedwhether to operate in the second charging mode. The device to be chargedsends a reply instruction of the first instruction to the power supplycircuit 10, in which the reply instruction of the first instruction isconfigured to indicate whether the device to be charged agrees tooperate in the second charging mode. When the device to be chargedagrees to operate in the second charging mode, the device to be chargedcontrols the power supply circuit 10 to charge the battery via the firstcharging channel.

In some embodiments, the device to be charged may perform bidirectionalcommunication with the power supply circuit 10 to control the output ofthe power supply circuit 10 in the second charging mode as follows. Thedevice to be charged performs the bidirectional communication with thepower supply circuit 10 to determine the charging voltage outputted bythe power supply circuit 10 in the second charging mode for charging thedevice to be charged.

In some embodiments, the device to be charged may perform thebidirectional communication with the power supply circuit 10 todetermine the charging voltage outputted by the power supply circuit 10in the second charging mode for charging the device to be charged asfollows. The device to be charged receives a second instruction sent bythe power supply circuit 10, in which the second instruction isconfigured to query whether the output voltage of the power supplycircuit 10 matches the present voltage of the battery in the device tobe charged. The device to be charged sends a reply instruction of thesecond instruction to the power supply circuit 10, in which the replyinstruction of the second instruction is configured to indicate that theoutput voltage of the power supply circuit 10 matches the presentvoltage of the battery, or is higher or lower than the present voltageof the battery. In some embodiments, the second instruction can beconfigured to query whether the present output voltage of the powersupply circuit 10 is suitable for being used as the charging voltageoutputted by the power supply circuit 10 in the second charging mode forcharging the device to be charged, and the reply instruction of thesecond instruction can be configured to indicate the present outputvoltage of the power supply circuit 10 is suitable, high or low.

When the present output voltage of the power supply circuit 10 matchesthe present voltage of the battery or the present output voltage of thepower supply circuit 10 is suitable for being used as the chargingvoltage outputted by the power supply circuit 10 in the second chargingmode for charging the device to be charged, it indicates that thepresent output voltage of the power supply circuit 10 may be slightlyhigher than the present voltage of the battery, and a difference betweenthe output voltage of the power supply circuit 10 and the presentvoltage of the battery is within a predetermined range (typically in anorder of hundreds of millivolts). When the present output voltage of thepower supply circuit 10 is higher than the present voltage of thebattery, it indicates that the difference between the output voltage ofthe power supply circuit 10 and the present voltage of the battery isabove the predetermined range. When the present output voltage of thepower supply circuit 10 is lower than the present voltage of thebattery, it indicates that the difference between the output voltage ofthe power supply circuit 10 and the present voltage of the battery isbelow the predetermined range.

In some embodiments, the device to be charged may perform thebidirectional communication with the power supply circuit 10 to controlthe output of the power supply circuit 10 in the second charging mode asfollows. The device to be charged may perform the bidirectionalcommunication with the power supply circuit 10 to determine the chargingcurrent outputted by the power supply circuit 10 in the second chargingmode for charging the device to be charged

In some embodiments, the device to be charged may perform thebidirectional communication with the power supply circuit 10 todetermine the charging current outputted by the power supply circuit 10in the second charging mode for charging the device to be charged asfollows. The device to be charged receives a third instruction sent bythe power supply circuit 10, in which the third instruction isconfigured to query a maximum charging current presently supported bythe device to be charged. The device to be charged sends a replyinstruction of the third instruction to the power supply circuit 10, inwhich the reply instruction of the third instruction is configured toindicate the maximum charging current presently supported by the deviceto be charged. The power supply circuit 10 determines the chargingcurrent outputted by the power supply circuit 10 in the second chargingmode for charging the device to be charged according to the maximumcharging current presently supported by the device to be charged.

The maximum charging current presently supported by the device to becharged may be derived according to the capacity of the battery of thedevice to be charged, a cell system, and the like, or may be a presetvalue.

It should be understood that, the device to be charged may determine thecharging current outputted by the power supply circuit 10 in the secondcharging mode for charging the device to be charged according to themaximum charging current presently supported by the device to be chargedin many ways. For example, the power supply circuit 10 may determine themaximum charging current presently supported by the device to be chargedas the charging current outputted by the power supply circuit 10 in thesecond charging mode for charging the device to be charged, or maydetermine the charging current outputted by the power supply circuit 10in the second charging mode for charging the device to be charged aftercomprehensively considering factors such as the maximum charging currentpresently supported by the device to be charged and its own currentoutput capability.

In some embodiments, the device to be charged may perform thebidirectional communication with the power supply circuit 10 to controlthe output of the power supply circuit 10 in the second charging mode asfollows. During charging in the second charging mode, the device to becharged performs the bidirectional communication with the power supplycircuit 10 to adjust the output current of the power supply circuit 10.

In some embodiments, the device to be charged may perform thebidirectional communication with the power supply circuit 10 to adjustthe output current of the power supply circuit 10 as follows. The deviceto be charged receives a fourth instruction sent by the power supplycircuit 10, in which the fourth instruction is configured to query apresent voltage of the battery in the device to be charged. The deviceto be charged sends a reply instruction of the fourth instruction to thepower supply circuit 10, in which the reply instruction of the fourthinstruction is configured to indicate the present voltage of thebattery. The power supply circuit 10 adjusts the output current of thepower supply circuit 10 according to the present voltage of the battery.

In some embodiments, the device to be charged may perform thebidirectional communication with the power supply circuit 10 to controlthe output of the power supply circuit 10 in the second charging mode asfollows. The device to be charged performs the bidirectionalcommunication with the power supply circuit 10 to determine whether thecharging interface is in poor contact.

In an embodiment, the device to be charged may perform the bidirectionalcommunication with the power supply circuit 10 to determine whether thecharging interface is in poor contact as follows. The device to becharged receives the fourth instruction sent by the power supply circuit10, in which the fourth instruction is configured to query the presentvoltage of the battery in the device to be charged. The device to becharged sends the reply instruction of the fourth instruction to thepower supply circuit 10, in which the reply instruction of the fourthinstruction is configured to indicate the present voltage of the batteryin the device to be charged. The power supply circuit 10 determineswhether the charging interface is in poor contact according to theoutput voltage of the power supply circuit 10 and the present voltage ofthe battery in the device to be charged. For example, when the powersupply circuit 10 determines a difference between the output voltage ofthe power supply circuit 10 and the present voltage of the battery inthe device to be charged is greater than a predetermined voltagethreshold, it indicates that an impedance obtained by dividing thevoltage difference by the present current value outputted by the powersupply circuit 10 is greater than a preset impedance threshold, and thusit can be determined that the charging interface is in poor contact.

In some embodiments, it can be determined by the device to be chargedwhether the charging interface is in poor contact. For example, thedevice to be charged sends a sixth instruction to the power supplycircuit 10, in which the sixth instruction is configured to query theoutput voltage of the power supply circuit 10. The device to be chargedreceives a reply instruction of the sixth instruction sent by the powersupply circuit 10, in which the reply instruction of the sixthinstruction is configured to indicate the output voltage of the powersupply circuit 10. The device to be charged determines whether thecharging interface is in poor contact according to the output voltage ofthe power supply circuit 10 and the present voltage of the battery inthe device to be charged. After the device to be charged determines thatthe charging interface is in poor contact, the device to be charged maysend a fifth instruction to the power supply circuit 10, in which thefifth instruction is configured to indicate that the charging interfaceis in poor contact. After receiving the fifth instruction, the powersupply circuit 10 may quit the second charging mode.

With reference to FIG. 10, the communication procedure between the powersupply circuit 10 and the device to be charged will be described indetail. It should be noted that, examples in FIG. 10 are merely used tohelp those skilled in the related art to understand embodiments of thepresent disclosure. The embodiments shall not be limited to the specificnumeric values or specific scenes. Apparently, various modifications andequivalents can be made by those skilled in the related art based onexamples in FIG. 10, and those modifications and equivalents shall fallwithin the protection scope of the present disclosure.

As illustrated in FIG. 10, the communication procedure between the powersupply circuit 10 and the device to be charged (or, referred to as thecommunication procedure of the fast charging) may include the followingfive stages.

Stage 1:

After the device to be charged is coupled to the power supply circuit10, the device to be charged may detect a type of the power supplycircuit 10 via the data wires D+ and D−. When detecting that the powersupply circuit 10 is a power supply circuit specifically used forcharging, such as an adapter, the device to be charged may absorbcurrent greater than a predetermined current threshold I2 (which may be,for example, 1A). When the power supply circuit 10 detects that theoutput current of the power supply circuit 10 is greater than or equalto I2 for a predetermined time period (for example, may be a continuoustime period T1), the power supply circuit 10 determines that the deviceto be charged has completed the recognition of the type of the powersupply device. Then, the power supply circuit 10 initiates a negotiationwith the device to be charged, and sends an instruction 1 (correspondingto the above-mentioned first instruction) to the device to be charged toquery whether the device to be charged agrees that the power supplycircuit 10 charges the device to be charged in the second charging mode.

When the power supply circuit 10 receives a reply instruction of theinstruction 1 sent by the device to be charged and the reply instructionof the instruction 1 indicates that the device to be charged disagreesthat the power supply circuit 10 charges the device to be charged in thesecond charging mode, the power supply circuit 10 detects the outputcurrent of the power supply circuit 10 again. When the output current ofthe power supply circuit 10 is still greater than or equal to I2 withina predetermined continuous time period (for example, may be a continuoustime period T1), the power supply circuit 10 sends the instruction 1again to the device to be charged to query whether the device to becharged agrees that the power supply circuit 10 charges the device to becharged in the second charging mode. The power supply circuit 10 repeatsthe above actions in stage 1, until the device to be charged agrees thatthe power supply circuit 10 charges the device to be charged in thesecond charging mode or until the output current of the power supplycircuit 10 is no longer greater than or equal to I2.

After the device to be charged agrees that the power supply circuit 10charges the device to be charged in the second charging mode, thecommunication procedure goes into stage 2

Stage 2:

For the output voltage of the power supply circuit 10, there may beseveral levels. The power supply circuit 10 sends an instruction 2(corresponding to the above-mentioned second instruction) to the deviceto be charged to query whether the output voltage of the power supplycircuit 10 (the present output voltage) matches the present voltage ofthe battery in the device to be charged.

The device to be charged sends a reply instruction of the instruction 2to the power supply circuit 10, for indicating that the output voltageof the power supply circuit 10 matches the present voltage of thebattery in the device to be charged, or is higher or lower than thepresent voltage of the battery in the device to be charged. When thereply instruction of the instruction 2 indicates that the output voltageof the power supply circuit 10 is higher or lower, the power supplycircuit 10 may adjust the output voltage of the power supply circuit 10to be lower or higher, and sends the instruction 2 to the device to becharged again to query whether the output voltage of the power supplycircuit 10 matches the present voltage of the battery. The above actionsin stage 2 are repeated, until the device to be charged determines thatthe output voltage of the power supply circuit 10 matches the presentvoltage of the battery in the device to be charged. Then, thecommunication procedure goes into stage 3. The output voltage of thepower supply circuit 10 may be adjusted in various ways. For example, aplurality of voltage levels from low to high may be set for the outputvoltage of the power supply circuit 10 in advance. The higher thevoltage level is, the larger the output voltage of the power supplycircuit 10 is. When the reply instruction of the instruction 2 indicatesthat the output voltage of the power supply circuit 10 is higher, thevoltage level of the output voltage of the power supply circuit 10 maybe reduced by one level from the present voltage level. When the replyinstruction of the instruction 2 indicates that the output voltage ofthe power supply circuit 10 is lower, the voltage level of the outputvoltage of the power supply circuit 10 may be increased by one levelfrom the present voltage level.

Stage 3:

The power supply circuit 10 sends an instruction 3 (corresponding to theabove-mentioned third instruction) to the device to be charged to querythe maximum charging current presently supported by the device to becharged. The device to be charged sends a reply instruction of theinstruction 3 to the power supply circuit 10 for indicating the maximumcharging current presently supported by the device to be charged, andthen the communication procedure goes into stage 4.

Stage 4:

The power supply circuit 10 determines the charging current outputted bythe power supply circuit 10 in the second charging mode for charging thedevice to be charged according to the maximum charging current presentlysupported by the device to be charged. Then, the communication proceduregoes into stage 5, i.e., the constant current charging stage.

Stage 5:

When the communication procedure goes into the constant current chargingstage, the power supply circuit 10 may send an instruction 4(corresponding to the above-mentioned fourth instruction) to the deviceto be charged at intervals to query the present voltage of the batteryin the device to be charged. The device to be charged may send a replyinstruction of the instruction 4 to the power supply circuit 10, to feedback the present voltage of the battery. The power supply circuit 10 maydetermine according to the present voltage of the battery whether thecharging interface is in poor contact and whether it is necessary todecrease the output current of the power supply circuit 10.

When the power supply circuit 10 determines that the charging interfaceis in poor contact, the power supply circuit 10 may send an instruction5 (corresponding to the above-mentioned fifth instruction) to the deviceto be charged, and the power supply circuit 10 would quit the secondcharging mode, and then the communication procedure is reset and goesinto stage 1 again.

In some embodiments, in stage 2, the time period from when the device tobe charged agrees the power supply circuit 10 to charge the device to becharged in the second charging mode to when the power supply circuit 10adjusts the output voltage of the power supply circuit 10 to a suitablecharging voltage may be controlled in a certain range. If the timeperiod exceeds a predetermined range, the power supply circuit 10 or thedevice to be charged may determine that the communication procedure isabnormal, such that the communication procedure is reset and goes intostage 1.

In some embodiments, in stage 2, when the output voltage of the powersupply circuit 10 is higher than the present voltage of the battery inthe device to be charged by ΔV (ΔV may be set to 200-500 mV), the deviceto be charged may send a reply instruction of the instruction 2 to thepower supply circuit 10, for indicating that the output voltage of thepower supply circuit 10 matches the voltage of the battery in the deviceto be charged.

In some embodiments, in stage 4, the adjusting speed of the outputcurrent of the power supply circuit 10 may be controlled to be in acertain range, thus avoiding an abnormity occurring in the chargingprocess due to the too fast adjusting speed.

In some embodiments, in stage 5, the variation degree of the outputcurrent of the power supply circuit 10 may be controlled to be less thanor equal to 5%.

In some embodiments, in stage 5, the power supply circuit 10 can monitorthe path impedance of a charging loop in real time. In detail, the powersupply circuit 10 can monitor the path impedance of the charging loopaccording to the output voltage of the power supply circuit 10, theoutput current of the power supply circuit 10 and the present voltage ofthe battery fed back by the device to be charged. When the pathimpedance of the charging loop is greater than a sum of the pathimpedance of the device to be charged and the impedance of the chargingwire, it may be considered that the charging interface is in poorcontact, and thus the power supply circuit 10 stops charging the deviceto be charged in the second charging mode.

In some embodiments, after the power supply circuit 10 starts to chargethe device to be charged in the second charging mode, time intervals ofcommunications between the power supply circuit 10 and the device to becharged may be controlled to be in a certain range, thus avoidingabnormity in the communication procedure due to the too short timeinterval of communications.

In some embodiments, the stop of the charging process (or the stop ofthe charging process that the power supply circuit 10 charges the deviceto be charged in the second charging mode) may be a recoverable stop oran unrecoverable stop.

For example, when it is detected that the battery in the device to becharged is fully charged or the charging interface is poor contact, thecharging process is stopped and the charging communication procedure isreset, and the charging process goes into stage 1 again. Then, thedevice to be charged disagrees that the power supply circuit 10 chargesthe device to be charged in the second charging mode, and thecommunication procedure would not go into stage 2. The stop of thecharging process in such a case may be considered as an unrecoverablestop.

For another example, when an abnormity occurs in the communicationbetween the power supply circuit 10 and the device to be charged, thecharging process is stopped and the charging communication procedure isreset, and the charging process goes into stage 1 again. Afterrequirements for stage 1 are met, the device to be charged agrees thatthe power supply circuit 10 charges the device to be charged in thesecond charging mode to recover the charging process. In this case, thestop of the charging process may be considered as a recoverable stop.

For another example, when the device to be charged detects that anabnormity occurs in the battery, the charging process is stopped and thecharging communication process is reset, and the charging process goesinto stage 1 again. The device to be charged then disagrees that thepower supply circuit 10 charges the device to be charged in the secondcharging mode. When the battery returns to normal and the requirementsfor stage 1 are met, the device to be charged agrees that the powersupply circuit 10 charges the device to be charged in the secondcharging mode. In this case, the stop of fast charging process may beconsidered as a recoverable stop.

Communication actions or operations illustrated in FIG. 10 are merelyexemplary. For example, in stage 1, after the device to be charged iscoupled to the power supply circuit 10, the handshake communicationbetween the device to be charged and the power supply circuit 10 may beinitiated by the device to be charged. In other words, the device to becharged sends an instruction 1 to query the power supply circuit 10whether to operate in the second charging mode. When the device to becharged receives a reply instruction indicating that the power supplycircuit 10 agrees to charge the device to be charged in the secondcharging mode from the power supply circuit 10, the power supply circuit10 starts to charge the battery in the device to be charged in thesecond charging mode. For another example, after stage 5, there may be aconstant voltage charging stage. In detail, in stage 5, the device to becharged may feed back the present voltage of the battery to the powersupply circuit 10. The charging process goes into the constant voltagecharging stage from the constant current charging stage when the presentvoltage of the battery reaches a voltage threshold for constant voltagecharging. During the constant voltage charging stage, the chargingcurrent decreases gradually. When the current reduces to a certainthreshold, it indicates that the battery in the device to be charged isfully charged, and the whole charging process is stopped.

Embodiments of the present disclosure further provide a power supplydevice. As illustrated in FIG. 11, the power supply device 1100 mayinclude a housing 100, a circuit board 200 and a power supply circuit300. The circuit board 200 may be enclosed by the housing 100. The powersupply circuit 300 may be positioned on the circuit board 200. The powersupply circuit 300 may be the power supply circuit 10 provided in anyembodiment of the present disclosure. The power supply device 1100 maybe a device specifically used for charging, such as an adapter or apower bank, or may be other devices capable of supplying power and dataservices, such as a computer.

The power supply circuit and the power supply device provided byembodiments of the present disclosure have been described above indetail with reference to FIGS. 1-11. A control method of a power supplycircuit provided by embodiments of the present disclosure will bedescribed below in detail with reference to FIG. 12. As illustrated inFIG. 12, the control method may include following blocks.

At block 1210, rectification is performed on input alternating currentto output a first voltage having a periodically changing voltage value.

At block 1220, the first voltage is modulated to generate a secondvoltage.

At block 1230, a third voltage is generated based on the second voltage.

At block 1240, rectification and filtering is performed on the thirdvoltage to generate a fourth voltage and a first current correspondingto the fourth voltage.

At block 1250, the first current is adjusted to generate an outputcurrent of the power supply circuit. The output current has a secondwaveform with a current value periodically changing, and each period ofthe second waveform includes a duration in which the current value is 0.

In some embodiments, the first current has a first waveform with acurrent value periodically changing, and the first current is adjusted,to switch off outputting the output current in a part of each period ofthe first waveform.

In some embodiments, the above part of each period is a duration inwhich a valley of the first waveform is located.

In some embodiments, the method may further include communicating with adevice to be charged, to adjust an output power of the power supplycircuit, such that an output voltage and/or the output current of thepower supply circuit matches a charging stage where a battery of thedevice to be charged is currently.

In some embodiments, the charging state in which the power supplycircuit charges the battery includes at least one of a trickle chargingstage, a constant current charging stage and a constant voltage chargingstage.

In some embodiments, communicating with the device to be charged, toadjust the output power of the power supply circuit, such that theoutput voltage and/or the output current of the power supply circuitmatches the charging stage where a battery of the device to be chargedis currently, may include: in the constant voltage charging stage,communicating with the device to be charged, to adjust the output powerof the power supply circuit, such that the output voltage of the powersupply circuit matches a charging voltage corresponding to the constantvoltage charging stage.

In some embodiments, communicating with the device to be charged, toadjust the output power of the power supply circuit, such that theoutput voltage and/or the output current of the power supply circuitmatches the charging stage where a battery of the device to be chargedis currently, may include: in the constant current charging stage,communicating with the device to be charged, to adjust the output powerof the power supply circuit, such that the output current of the powersupply circuit matches a charging current corresponding to the constantcurrent charging stage.

With respect to the details of the control method, reference can be madeto the above description regarding the power supply circuit, which willnot be elaborated here for simplicity.

In above embodiments, it is possible to implement the embodiments fullyor partially by software, hardware, firmware or any other combination.When implemented by software, it is possible to implement theembodiments fully or partially in a form of computer program products.The computer program product includes one or more computer instructions.When the computer program instructions are loaded and executed by thecomputer, procedures or functions according to embodiments of thepresent disclosure are fully or partially generated. The computer may bea general-purpose computer, a special-purpose computer, a computernetwork, or any other programmable device. The computer instructions maybe stored in a computer readable storage medium, or may be transmittedfrom one computer readable storage medium to another computer readablestorage medium. For example, the computer instructions may betransmitted from one website, computer, server or data center to anotherwebsite, computer, server or data center in a wired manner (for example,via coaxial cables, fiber optics, or DSL (digital subscriber line)) orin a wireless manner (for example, via infrared, WiFi or microwave). Thecomputer readable storage medium may be any available medium that areaccessible by the computer, or a data storage device such as a server ora data center integrated with one or more available medium. Theavailable medium may be magnetic medium (for example, floppy disk, harddisk and tape), optical medium (for example, DVD (digital video disc)),or semiconductor medium (for example, SSD (solid state disk)).

Those skilled in the art could be aware that, exemplary units andalgorithm steps described in combination with embodiments disclosedherein may be implemented by electronic hardware, or by a combination ofcomputer software and electronic hardware. Whether these functions areexecuted by hardware or software is dependent on particular use anddesign constraints of the technical solutions. Professionals may adoptdifferent methods for different particular uses to implement describedfunctions, which should not be regarded as going beyond the scope of thepresent disclosure.

In several embodiments provided by the present disclosure, it should beunderstood that, the disclosed system, device and method may beimplemented in other ways. For example, the device embodiments describedabove are merely illustrative. For example, the units are merely dividedaccording to logic functions, and can be divided in other ways in actualimplementation. For example, a plurality of units or components may becombined or may be integrated into another system, or some features maybe ignored or not executed. In addition, the mutual coupling or directcoupling or communication connection illustrated or discussed may be viasome interfaces, or direct coupling or communication connection ofdevices or units may be in an electrical, mechanical, or other form.

Units illustrated as separate components may be or may not be physicallyseparated, and components illustrated as units may be or may not bephysical units, i.e., may be located at a same place, or may bedistributed onto multiple network units. Some or all of the units may beselected to implement the purpose of the solution in an embodimentaccording to actual demands.

Moreover, respective functional units in respective embodiments of thepresent disclosure may be integrated in one processing unit, or therespective units may be separate physical existence, or two or moreunits may be integrated in one unit.

Above description is merely specific implementation of the presentdisclosure. However, the protection scope of the present disclosure isnot limited to this. Any change or substitute that is conceivable bythose skilled in the art should be in the protection scope of thepresent disclosure. Thus, the protection scope of the present disclosureshould be defined as the protection scope of claims.

What is claimed is:
 1. A power supply circuit, comprising: a primaryrectifier unit, configured to perform rectification on input alternatingcurrent to output a first voltage having a periodically changing voltagevalue; a modulation unit, configured to modulate the first voltage togenerate a second voltage; a transformer, configured to generate a thirdvoltage based on the second voltage; a secondary rectifier and filteringunit, configured to perform rectification and filtering on the thirdvoltage to generate a fourth voltage and a first current correspondingto the fourth voltage; and a control unit, configured to adjust thefirst current to generate an output current of the power supply circuit,the output current having a second waveform with a current valueperiodically changing, and each period of the second waveform containinga duration in which the current value is 0; wherein, the first currenthas a first waveform with a current value periodically changing, thecontrol unit is configured to control the power supply circuit to stopoutputting in a duration where a valley of the first waveform islocated, such that each period of the second waveform containing theduration in which the current value is
 0. 2. The power supply circuit ofclaim 1, wherein the power supply circuit further comprises a firstswitch unit configured to control a charging line of the power supplycircuit to switch on or off; and the control unit is further configuredto control the first switch unit to switch off in a part of each periodof the first waveform.
 3. The power supply circuit of claim 1, whereinthe power supply circuit further comprises a load circuit coupled inparallel with a charging loop of the power supply circuit and a secondswitch unit configured to control the load circuit to switch on or off;the control unit is configured to control the second switch unit toswitch on in a part of each period of the first waveform; and the loadcircuit is configured to consume electric energy transmitted on thecharging loop when the second switch unit is switched on.
 4. The powersupply circuit of claim 2, wherein the part of each period is a durationin which a valley of the first waveform is located.
 5. The power supplycircuit of claim 1, wherein the secondary rectifier and filtering unitcomprises a third switch unit; the third switch unit is configured tocontrol a filtering circuit in the secondary rectifier and filteringunit to switch on or off; the control unit is configured to control thethird switch unit to switch off in a target duration of each period ofthe first waveform, in which the target duration is a duration in whicha valley of the first waveform is located.
 6. The power supply circuitof claim 5, wherein the filtering circuit comprises a filteringcapacitor; the third switch unit comprises a MOS (Metal OxideSemiconductor) transistor; a positive electrode of the filteringcapacitor is coupled to a charging line of the power supply circuit, anegative electrode of the filtering capacitor is coupled to a source ofthe MOS transistor, a drain of the MOS transistor is grounded, and agate of the MOS transistor is coupled to the control unit.
 7. The powersupply circuit of claim 1, wherein the control unit is furtherconfigured to communicate with a device to be charged, to adjust anoutput power of the power supply circuit, such that an output voltageand/or the output current of the power supply circuit matches a chargingstage where a battery of the device to be charged is currently.
 8. Thepower supply circuit of claim 7, wherein the charging stage in which thepower supply circuit charges the battery comprises at least one of atrickle charging stage, a constant current charging stage and a constantvoltage charging stage.
 9. The power supply circuit of claim 8, whereinthe control unit is configured to: in the constant voltage chargingstage, communicate with the device to be charged, to adjust the outputpower of the power supply circuit, such that the output voltage of thepower supply circuit matches a charging voltage corresponding to theconstant voltage charging stage.
 10. The power supply circuit of claim8, wherein the control unit is configured to: in the constant currentcharging stage, communicate with the device to be charged, to adjust theoutput power of the power supply circuit, such that the output currentof the power supply circuit matches a charging current corresponding tothe constant current charging stage.
 11. A power supply device,comprising a housing, a circuit board, and a power supply circuit,wherein the circuit board is enclosed by the housing; the power supplycircuit is positioned on the circuit board; and the power supply circuitcomprises: a primary rectifier unit, configured to perform rectificationon input alternating current to output a first voltage having aperiodically changing voltage value; a modulation unit, configured tomodulate the first voltage to generate a second voltage; a transformer,configured to generate a third voltage based on the second voltage; asecondary rectifier and filtering unit, configured to performrectification and filtering on the third voltage to generate a fourthvoltage and a first current corresponding to the fourth voltage; and acontrol unit, configured to adjust the first current to generate anoutput current of the power supply circuit, the output current having asecond waveform with a current value periodically changing, and eachperiod of the second waveform containing a duration in which the currentvalue is 0; wherein, the first current has a first waveform with acurrent value periodically changing, the control unit is configured tocontrol the power supply circuit to stop outputting in a duration wherea valley of the first waveform is located, such that each period of thesecond waveform containing the duration in which the current value is 0.12. The power supply device of claim 11, wherein the power supply deviceis an adapter.
 13. A control method of a power supply circuit,comprising: performing rectification on input alternating current tooutput a first voltage having a periodically changing voltage value;modulating the first voltage to generate a second voltage; generating athird voltage based on the second voltage; performing rectification andfiltering on the third voltage to generate a fourth voltage and a firstcurrent corresponding to the fourth voltage; and adjusting the firstcurrent to generate an output current of the power supply circuit, theoutput current having a second waveform with a current valueperiodically changing, and each period of the second waveform containinga duration in which the current value is 0; wherein, the first currenthas a first waveform with a current value periodically changing,adjusting the first current comprises: controlling the power supplycircuit to stop outputting in a duration where a valley of the firstwaveform is located, such that each period of the second waveformcontaining the duration in which the current value is
 0. 14. The controlmethod of claim 13, wherein adjusting the first current comprises:adjusting the first current to switch off generating the output currentin a part of each period of the first waveform.
 15. The control methodof claim 14, wherein the part of each period is a duration in which avalley of the first waveform is located.
 16. The control method of claim13, further comprising: communicating with a device to be charged, toadjust an output power of the power supply circuit, such that an outputvoltage and/or the output current of the power supply circuit matches acharging stage where a battery of the device to be charged is currently.17. The control method of claim 16, wherein the charging stage in whichthe power supply circuit charges the battery comprises at least one of atrickle charging stage, a constant current charging stage and a constantvoltage charging stage.
 18. The control method of claim 17, whereincommunicating with the device to be charged, to adjust the output powerof the power supply circuit, such that the output voltage and/or theoutput current of the power supply circuit matches the charging stagewhere the battery of the device to be charged is currently, comprises:in the constant voltage charging stage, communicating with the device tobe charged, to adjust the output power of the power supply circuit, suchthat the output voltage of the power supply circuit matches a chargingvoltage corresponding to the constant voltage charging stage.
 19. Thecontrol method of claim 17, wherein communicating with the device to becharged, to adjust the output power of the power supply circuit, suchthat the output voltage and/or the output current of the power supplycircuit matches the charging stage where the battery of the device to becharged is currently, comprises: in the constant current charging stage,communicating with the device to be charged, to adjust the output powerof the power supply circuit, such that the output current of the powersupply circuit matches a charging current corresponding to the constantcurrent charging stage.